1. Field of the Invention
The present invention relates generally to cellular/PCS (Personal Communications Services) telephone communications. Specifically, the present invention relates to detecting cloning fraud in a cellular/PCS environment.
2. Related Art
Cellular mobile telephone systems provide direct-dial telephone service to mobile users by using radio transmission. The service area of a cellular mobile telephone system is divided into regions called cells. Within each cell is a base station which includes a transmitter and a receiver. Each base station is connected to a mobile switching center (MSC) which processes calls to and from mobile users located in the cell. Each transmitter and receiver operates on a voice channel (frequency). A single channel may be used for many simultaneous conversations (voice signals) in cells which are sufficiently separated from one another such that excessive interference is avoided. However, as the number of mobile users increases within a cell, the cell may become too crowded to provide adequate separation. When a cell becomes overcrowded, the cell must be split into smaller cells with each cell covering a smaller geographic area. Each new cell requires a new base station which is connected to the original MSC. Thus, as the number of cells increases, each MSC may be processing calls for multiple cells.
As a mobile user travels with his cellular telephone powered up, the cellular telephone autonomously registers the mobile user by sending signals with information identifying the mobile user to the MSC serving the cell where the mobile user is currently located. The sending and receipt of such information is referred to as registration notification. The information included in a registration notification is the mobile user""s mobile identification number (MIN) and an electronic serial number (ESN). The MIN uniquely identifies each mobile user in a manner similar to a conventional telephone number. The ESN is encoded into each cellular telephone. The ESN functions as a security password verifying the validity of the MIN and allowing the mobile user access to the cellular mobile telephone system.
The MSC collects registration notifications and provides them to other facilities in the cellular mobile telephone system. These facilities primarily use the registration notifications to facilitate incoming and outgoing calls. Typically, a mobile user subscribes for services with the MSC covering the cell, or group of cells, where the mobile user primarily resides or conducts business. This MSC is referred to as the mobile user""s home MSC. All other MSCs in the cellular mobile telephone system are known as visited MSCs with respect to the mobile user. When a mobile user ventures beyond the cells covered by the home MSC, the mobile user is said to be xe2x80x9cvisiting.xe2x80x9d For purposes of this discussion, a mobile user inside a cell of a visited MSC is referred to as a visiting mobile user.
When a mobile user powers on his cellular telephone or crosses cell boundaries covered by different MSCs, the cellular telephone, at some point, autonomously sends a signal representing a registration notification. The MSC covering the cell (i.e., either a home MSC or a visited MSC) receives the registration notification. Based on the MIN and ESN contained in the registration notification, the MSC queries a Roamer Validation and Call Delivery (RVCD) facility to validate the mobile user""s subscription information. The RVCD stores the subscription information for all mobile users in the cellular mobile telephone system in a Home Location Register (HLR). The HLR identifies each of the mobile users home MSC, the services to which each mobile user is subscribed, and whether each subscription is valid.
After receiving a query from the MSC, the RVCD responds by sending the requested the information included in the HLR back to the querying MSC. The MSC maintains this information to provide cellular mobile telephone services to the mobile user as long as the mobile user remains in cells covered by the MSC.
Registration notification is important for several reasons. Primarily, registration notification is used to provide cellular mobile telephone services to mobile users outside of the cells of the home MSC (as described above). Thus, a mobile user can utilize cellular mobile telephone services throughout the cellular mobile telephone system.
Registration notification is also important for routing incoming calls to mobile users. When an incoming call is to be routed to a mobile user, the mobile user must be located so that the call can be routed through the proper MSC to the mobile user. In the case of a conventional telephone user (i.e., not a mobile user) attempting to place a call to a mobile user, the home MSC receives the incoming call from the regular telephone user and determines whether the mobile user is active, or operating, in the cell of the home MSC. If the mobile user is not active within the cell of the home MSC, the mobile user may: 1) not have his telephone powered up, or 2) be active in the cell of a visited MSC. In the first case, the incoming call cannot be routed to the mobile user. In the second case, the RVCD attempts to locate the mobile user within the cellular telephone system.
The RVCD functions as a clearing house for a cellular mobile telephone system. Specifically, the RVCD validates mobile users and manages activation, deactivation, and changes in subscription profiles of mobile users. The RVCD also stores a copy of each registration notification received from the MSCs. Furthermore, the RVCD updates the HLR to indicate the MSC where the latest registration notification originated (this is called the originating MSC). This allows the RVCD to track where each mobile user is currently located in the cellular mobile telephone system.
Tracking mobile users within the cellular mobile telephone system serves to facilitate the routing of incoming calls to mobile users. When an incoming call is placed to a mobile user who is not within the cell of the home MSC, the home MSC can query the RVCD to locate the mobile user based on the origination of the registration notification maintained in the HLR. The the incoming call can then be routed to the originating MSC which connects the incoming call via radio communication signals to the mobile user. In the preferred embodiment, two RVCD systems are used in parallel to provide backup for the cellular mobile telephone system in case one RVCD should fail.
A problem existing in current cellular mobile telephone systems is cloning fraud. Cloning fraud occurs when one mobile user (called an unauthorized user) obtains and fraudulently uses the MIN and ESN registered to another mobile user (called an authorized user) in order to obtain xe2x80x9cfreexe2x80x9d service. As used herein, the term xe2x80x9cvalid MINxe2x80x9d refers to a MIN when being used by an authorized mobile user. The term xe2x80x9ccloned MINxe2x80x9d refers to a MIN when being used by an unauthorized mobile user.
The cellular mobile telephone system uses the MIN and ESN associated with each mobile telephone call to bill the authorized mobile user registered with that MIN and ESN. When a MIN and ESN are xe2x80x9cclonedxe2x80x9d, the authorized mobile user gets billed for calls made with the valid MIN as well as those calls made using the cloned MIN. Cloning fraud costs the cellular telephone industry millions of dollars in lost revenue each year. What is needed is a means for detecting cloning fraud in a cellular/PCS environment.
The present invention is directed to a system 200 and method for proactively detecting cloning fraud in a cellular/PCS (Personal Communications Services) environment. According to the invention, the system detects cloning fraud by comparing the time and location of registration notifications having the same mobile identification number (MIN). Cloning fraud is reported when the computed time difference between such registration notifications is less than a reasonable travel time between the cells of the originating mobile switching centers (originating MSCs).
Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.